JPS61113896A - Improvement in production of paper and corrugated board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to paper or cardboard manufacturing. More particularly, the present invention relates to a process for producing paper or board in which organic polysaccharides are added to a mixture or applied to a web of fibers during paper or board production. In particular, the present invention relates to papers produced by such a method that have improved strength or surface properties. Improved additive materials also constitute a feature of the invention.

BACKGROUND OF THE INVENTION It is well known to add one or more additives during the early stages of paper or board production to increase interfiber bonding and thereby increase the strength of the final paper or mailer. Additives are usually polysaccharides and their chemical derivatives such as starch and cellulose, and other organic substances that can form chemical bonds with the underlying cellulose of the paper or cardboard web. This cellulose was modified by the paper or board manufacturer during the early stages of manufacturing prior to web formation to aid in web formation.

The additives described herein can be added to the pulp itself or added at an early stage of paper web formation (wet-end addition) (i.e., when the moisture content is reduced from about 9% to about 30%). ). In such cases the additive is distributed substantially uniformly throughout the thickness of the paper or cardboard. It is also known to conveniently apply additives to one or both sides of the formed web in a manufacturing step following web formation when the moisture has been reduced to 2-20% by weight of the web.

Size-Press Aaat Lion, named after the relevant part of the paper machine
are examples of known methods, in which additives can be added at this stage using their solutions or dispersions, foamed liquids or dry powders. The size press process is a useful method for applying materials to paper or cardboard, but the equipment must be purchased and
And they are known to be expensive and cumbersome to install. A large amount of energy is also consumed in operating the machine and performing the intensive special drying operations that result from the use of size presses.

Since the application of substances in the size press is carried out using aqueous solutions or dispersions, special drying equipment must be installed in addition to that used to dry the paper or cardboard before they pass through the size press. It is necessary to prepare. This special drying requires special drying equipment at 30%'', which increases the energy consumed during paper or board production by an additional 30%.

Problem to be Solved by the Invention The present invention relates to the behavior of dispersions or solutions of polysaccharide additives during transfer, handling and subsequent heating, and the present invention relates to the study of the fluidity of said dispersions or solutions. based on.

When aqueous dispersions of starch are subjected to high shear (e.g., high velocity flow through a restricting hole, such as is commonly used to produce a spray), they exhibit a slight girattancy (response to the flow, which increases as the shear rate increases). resistance or apparent viscosity). As a result of this increase, flow is restricted or stopped.

Dilatancy is particularly pronounced in starch suspensions when starch accounts for more than 5% of the total fluid. This stop is well known to starch users who wish to spray suspensions of raw or modified starch as an aid to various industrial processes such as paper and board applications during and after manufacture. There is.

Aqueous suspensions of starch are also prone to sediment formation due to gravitational or inertial forces acting on particulate matter suspended in water. Such sediment is the cause of equipment breakdown. In order to prevent or reduce the occurrence of settling, it has hitherto been customary to increase the viscosity of the suspension by raising the temperature of the starch to a temperature above that at which the individual particles break. This process is generally done by one cooking process.
This process makes starch water-efficient.
・) Glues are formed that reduce the tendency of particles to settle. Alternatively, it is customary to add substances that reduce the settling process by increasing the viscosity of the aqueous phase of the suspension. Such viscosity increasing substances include cold water soluble derivatives of starch or cellulose and many high molecular weight polyhydric substances such as polyethylene oxide ethers, polyvinyl alcohol, as well as swelling clays such as bentonite, attapulgide, laponite etc. (can increase the viscosity of the suspension).

However, the above procedure produces a poor spray. This is because the fluid requires high pump pressure to achieve a sufficiently high degree of turbulence in the spray head to produce the fine droplets desired for the applications described herein. Such high pump pressures frequently cause equipment failures due to the inherent tendency of starch suspensions to become dilatant.

The present invention has discovered a process for making paper or gable paper in which one or more additives are also present in the strength-affecting starch suspension.

SUMMARY OF THE INVENTION In accordance with the present invention, an aqueous suspension of starch is provided which contains a small amount of a hydrophilic polymeric viscosity enhancer and is thus stabilized to prevent settling of suspended starch particles. Paper or?
- In a method of applying a viscous treatment agent during the production of paper, there is also provided a method for stabilizing the application of said agent by means of a rotary atomizer.

It can be seen that the invention consists of three aspects. - In one aspect, the invention provides a method for the production of said paper or board, in which an aqueous suspension of starch is applied to the paper web during or after the paper or board production. In said method, the water-utilizing polymer is present in the suspension in such an amount that it changes the rheology of the suspension so that it becomes more pseudoplastic, thus facilitating its application to the web. Because pseudoplasticity (also known as viscoelasticity or shear thinning) according to the present invention
This is because the fluid can have sufficient viscosity to prevent settling of dispersed particles, such as starch, under the low shear rates experienced during storage or during transportation. Moreover, when the fluid is exposed to high shear rates, such as occurs when it is ejected from a narrow hole, such as the nozzle of a spray jet, said fluid is applied as a solution or suspension to the paper or cardboard at an early manufacturing stage. It exhibits a sufficiently low viscosity that suitable droplets can be formed.

In another aspect, the present invention provides a method of making paper or sol paper in which an aqueous solution of a water-utilizing polymer is applied to the paper web during or after production.

In said method, a water-soluble polymeric substance is present in solution that is capable of forming a continuous film at or near the surface of the paper or cardboard. This polymer can be applied alone to take advantage of the spray dispersion (IJ pieta) described in the present invention. Alternatively, the polymer can be applied with starch and the rheology-modified polymer.

In each of the aforementioned surfaces, the hydraulic polymer is non-ionic or ionic, preferably anionic.

The polymer may be a sodium, potassium or ammonium salt of a polycargenic acid in which the carboxyl units are attached to a long chain polyhydroxyl polymer (e.g. EVA polysaccharide). The polymers are based on glucose, mannose, galactose, pyranose, amylose, etc. and their hybrid derivatives including acids such as glucuronic acid.

Typical polymers include the sodium, potassium and ammonium salts of carboxymethylcellulose, and complex polymers obtained by fermentation of suitable sugar-based media by the microorganism Xanthomonai campus-trim, commonly known as Xanthan gum. It can also be one of the water-soluble salts of polyacrylic acid, polymethacrylic acid and other similar water-soluble salts. The actual polysaccharide and its most preferred derivative depends on the main important aspects of the invention.

In another aspect, the present invention provides a method for producing paper or cardboard in which a suspension or solution of a substance in water or other liquid is applied by means of a rotary atomizer. Although the 1 and 4X solutions can be applied to the surface of the paper by conventional high-pressure spraying, it is preferred to use rotary atomizers, which are well known in agricultural technology but have not hitherto been used in paper production.

This atomizer is called “Micron Microma”.
It is available in several similar products, including devices sold under several registered trademarks such as x' and "La1y Hydraspin." This better atomizer has British Patent Nos. 20042041 and 20042041.
No. 4205B and No. 2004206B, and defined in the first claims of these patents. These atomizers and other similar devices comprise a flat-headed hollow conical shell set on a vertical axis with a narrow end at the bottom.

The construction of the atomizer is shown diagrammatically in FIG. 1 of the accompanying drawings, which consists of a biconical cross-section. This atomizer comprises a fixed inner cone 1 surrounded by an outer cone 2 mounted on a bottom bearing 3 located at the end of a central shaft 4. A central nozzle 5 is arranged to feed the incoming fluid. The outer cone 2 is mounted on top with drive means including a belt drive system 7.8 connected to an electric motor 9 and a top bearing 6. The top outer end of the outer cone 2 is provided with teeth 10 and a circumferential guard ring. The fluid to be sprayed passes through the mouth of the pump and into the spinning cone 2.
, and is subsequently conveyed upwards and outwards across the inner surface of the spinning cone 2 until the fluid exits the cone along the widest upper circumference. The size of the droplet produced by this movement of fluid is controlled in part by serrating the upper end of the cone in the form of teeth 10 disposed radially around its upper surface. The cone can be driven by an electric, pneumatic or hydraulic prime mover with a suitable drive, with suitable bearings to rigidly support the cone on the mount. In the case of hydraulic motors, the drive energy can be transferred to the motor by a conventional hydraulic pressure generating pump and is limited to the so-called hydraulic fluid. Alternatively, drive energy can be conveyed by arranging that the aqueous starch suspension or other fluid to be applied to the paper drives a turbine connected to the spinning cone.

For a given atomizer and a liquid with given rheological properties, when spun at a given speed, uniformly sized droplets are produced. It is envisaged that the droplet size can be selected to meet the specific requirements of the user by choosing an appropriate combination of atomizer placement, fluid rheology and rotational speed.

Although each quarter meter governing droplet size can be adjusted independently of the others and also independently of the flow rate of the suspension or solution applied to the paper surface, it is known in the industry that In the case of the conventional atomizing nozzles used previously, the droplet size depends on the pressure of the droplet across the nozzle;
And it governs the flow velocity.

Since the droplets produced by the atomizer are of virtually uniform size, they follow similar trajectories and therefore the pattern on the paper surface can be controlled almost identically;
and therefore applies equally. If the droplets are ejected from a rotating atomizer set to rotate on a vertical axis, the droplets will follow a horizontal trajectory. It is therefore assumed that each droplet moves along a path determined by horizontal forces caused by tangential motion and gravity. If you position the atomizer so that the bottom of the cone is close to the surface to which you apply the fluid, the droplets will move vertically under gravity for about 20 minutes and will be sprayed at high speeds from a conventional pressure-operated spray nozzle. It is estimated that the droplet is moving at a much slower speed than a similar droplet ejected by. This is particularly advantageous when the fluid is to be applied to the surface of the paper or cardboard in the early stages of manufacture, when the moisture content of the paper is high and the strength of the paper is therefore low.

As the fluid passes through the paper machine, one or more atomizers are secured to the boom set to allow application of the fluid to the top or bottom of the paper or cardboard. If desired, a portion of the circumference of the spinning cone can be surrounded by a shield 1' to restrict the passage of droplets to the opposite space along the diameter of the shield. This allows the fluid to be applied directly when required by the user. Fluid collected by the shield can be returned to a holding tank or conveniently back into the fluid circulation system.

A first aspect of the invention relates to suspension rheology.

It is well known that the velocity of a liquid at which it changes from laminar or static to turbulent flow is defined by the Reynolds equation, as shown below.

d, ma, r NR=□・K ■ In the formula, Nr = Reynolds number of the fluid d = fluid density V = fluid velocity r = radius of the hole or pipe through which the fluid flows = constant of proportionality ■ = fluid viscosity 1? It is known that turbulence occurs when the Reynolds number exceeds 2000, if the ramometer is expressed in units of eggs. If the V (viscosity) value of a particular fluid is low, the Reynolds number will be high and therefore turbulence will occur under conditions where the high viscosity fluid flows in laminar fashion.

Furthermore, the lower viscosity allows the fluid to flow at higher speeds in a given environment, and therefore the Neunorz number increases further and turbulence of the fluid occurs.

It is well known that optimal efficiency of a spray or atomization system requires that the fluid be in a turbulent state at the point at which breakage into droplets occurs. In other words, optimal droplet formation occurs when the fluid viscosity is low.

Therefore, if two fluids with different viscosities are compared under similar conditions of flow defined by the parameters used in the Reynolds equation, it can be assumed that better spray efficiency is obtained in lower viscosity fluids.

By further considering the first aspect, i.e. the rheology of starch suspensions, the viscosity or resistance to deformation in a fluid can be determined when the fluid is stationary or nearly stationary, i.e. under conditions of low shear rates. It is required to be as high as possible. Starch or similar suspensions can be stabilized if the viscosity of the fluid is increased by cooking at least some of the starch or by adding said soluble polymeric substances, i.e. the gravity of the starch particles or It is taught in the prior art that solidification under inertial forces is prevented. Stokes' law shows this by calculating that the external force υ acting on suspended particles is inversely proportional to the viscosity of the fluid. However, such treatment causes high viscosities which are detrimental to the efficiency of the spray equipment. It is therefore assumed that the rheology of the fluid in which the starch is suspended must exhibit high viscosity at low shear rates to prevent settling of the starch particles. At the same time, it must exhibit low viscosity at high shear rates to ensure sufficient turbulence to produce droplets of optimum size and optimum particle size distribution. It is well known that the viscosity of solutions of polymeric materials falls more rapidly as the shear rate or flow rate through a given hole increases. This is illustrated in the table below which compares the in-water viscosities of several well known high viscosity polymeric materials over a range of shear rates. The viscosity and shear rate of each were measured with a Brookfield viscometer equipped with a coaxial gob and cylinder attachment sold under the name SC4 Small Sample Adapter.

CMC1800013000840060004300
300019001400HgC8000650050
003800270019001100GG 1
1009100580039002400150070
0XG 3200017000750038001
9001100450240XG' 660 5
50 a 430400340260210 If a substance capable of providing a highly pseudoaltotic aqueous solution is added to a small proportion of starch powder or incorporated into a suspension of starch,
The starch can be stored for long periods of time in an aqueous suspension, transported through limited pores without forming stains/sees, and the suspension can be stored on the surface of the paper during manufacturing. It has been found according to the invention that they quickly transform into droplets of a sufficiently small size to enable their use as a means of uniformly applying starch to such surfaces.

Preferred polymers for rheological influence purposes dissolve in xanthan gum and water to produce solutions with very high viscosities at low shear rates and relatively low viscosities at high shear rates compared to other commercially available polymers. It is a polysaccharide similar to Uru. This is shown in Table 1. A solution of xanthan gum is 1
It exhibits little change in its physical properties, such as rheology, over the temperature range commonly experienced in paper mills and other closed industrial facilities. These properties show negligible changes when ionic and other dissolved substances are present with xanthan gum. This is particularly important when preparing starch suspensions using water of unknown composition, e.g. when recycled water with different hardness and different salt content at different temperatures is used for such preparation. It is.

The V-ology-affecting properties of the Kisa/Tan gum are such that the presence of the KISA/TAN gum in suspension greatly reduces the tendency of starch particles to settle or form recalcitrant sediments. This is particularly important when applying it in the form of

The presence of xanthan gum in starch suspensions as described in the present invention allows the user to store such suspensions for long periods of time and allows the user to store the starch in the form of a slurry. to be able to be transported to the final destination. There is no need for special shaking devices to be installed in the slurry containers used for transporting and storing the slurry. The convenience of transporting and storing starch suspensions with the addition of xanthan gum is particularly important in that such suspensions are available as residues from the food manufacturing process in which they are involved. It is economically advantageous to supply starch in the form of a concentrated suspension or slurry, rather than having to extract, dry and subsequently reconstitute the starch before use. The present invention provides an economical method of storing and transporting such starch suspensions or slurries for the benefit of the starch and paper industry.

The present invention also provides that the presence of xanthan gum in starch suspensions overcomes the tendency of such suspensions to exhibit dilatancy, which can best be described as an increase in resistance to flow or viscosity with increasing shear rate. was discovered by. Guillatancy is a problem in starch and other suspensions because dilatant fluids tend to stop flowing under conditions of high shear rates, such as those that occur in pumps and control valves, in bends and restrictors in pipes, and in the nozzles of conventional spray equipment. This is a condition that should be avoided when handling liquids. The presence of xanthan gum in such suspensions therefore prevents the well-known and difficult tendency of suspensions to cause blockages in the equipment used to convey them, especially in the nozzles of conventional spray equipment. useful for.

The weight of xanthan gum varies between 0.025% and 1.0% of the water used to prepare the starch suspension. In the case of suspensions prepared from dry powdered starch, the xanthan gum can be incorporated into the starch powder along with other polymeric materials as desired so that they are present in the slurry in the proportions during use. In the case of starch already prepared in the form of a suspension as described above, it is advantageous to add xanthan gum at an early stage to facilitate transport and long storage.

A second aspect of the invention relates to the film-forming properties of certain polymers. That is, the polymer is dissolved in water or otherwise dispersed in water, and the starch suspension is prepared in a similar manner to the process already described for application to paper or cardboard during production. Concerning film-forming properties when applied in droplet form. Preferred polymers are carboxymethyl starch or carboxymethyl cellulose or alkali metal salts of alginic acid or polyacrylic acid and their homologs, or preferably carboxymethyl starch or carboxymethyl cellulose, commonly known as SCMC or CMC. It is a polysaccharide such as the sodium salt of oxymethylcellulose. The polymers can be applied with or without starch as described herein to provide various benefits to meet user requirements.

Force kg Kisimechi * to '-7 is 0.35 to 1.4 force
11 degree of redexymethylation (related to the three labile hydroxy groups theoretically available for substitution on each anhydroglucose ring within the cellulose chain) and total molecular weight 1
5,000-800,000, preferably 5o, oo
o~250.000. The presence of SCMC or other polymers described in the aqueous starch suspension has the effect of lowering the temperature at which the starch particles break down and form a slug (dulling temperature) as exemplified by a rapid increase in viscosity. have For example, molecular weight approximately i o o, o
SCMC4 with o o and carboxymethylation degree of 0.85
1 part to 16 parts of wheat starch. The gluing temperature of a starch suspension of 20% by weight was set to 64 Celsius.
The effect of this was to lower the temperature from s) degrees to 59 degrees Celsius. This reduction in gluing temperature is important in the paper or sol paper manufacturing process in that low temperature dalification of starch is known to improve the beneficial effects of the addition of Denzone to cellulose. The addition of such SCMC to starch is thus an important and heretofore unexpected method of improving the economics of operating a paper or board manufacturing process.

The amount of these polymers or mixtures thereof can be up to 10% (usually 0.25%) of the weight of the water used to deliver the additive through the conventional spray or atomization distributor described herein.
% to 7.5%).

The presence of xanthan gum as part of an aqueous dispersion of starch or other water-soluble polymers such as SCMC increases the resistance to flow of the dispersion, and thus controls the rate at which the dispersion penetrates the paper after application. Helpful. It is therefore assumed that the presence of xanthancho95 keeps the dispersion at or near the surface of the paper even when the paper contains a high proportion of water, such as occurs during the early stages of paper manufacturing.

In the method of the present invention, starch is 0.5% of the dry paper mold lid.
It is expected that .about.10% will be applied to paper or cardboard by the method described herein. Rheology-affecting substances, such as xanthan gum, may also be present in sufficient amounts to prevent starch settling or in sufficient total to prevent the dispersion from becoming giratant (unsuitable for transport through the restriction hole). expected. It is also contemplated that so-called water-soluble polymers, such as those described above, may be applied to paper or board by the methods described herein to provide improvements to the paper or board or to increase the usefulness of the applied starch. The starch and the polymer may be blended together in dry form, or the respective dispersions or solutions may be mixed together and the mixture obtained by the method described herein may be applied, or the dispersion or solution of the respective substances may be blended together. It is envisaged that the blending will be accomplished by having two or more spray distributors each applied, each set to apply the respective material at the most appropriate point in paper or board production.

Although the invention has been defined above as a method for making paper or cardboard, it will be appreciated that paper or cardboard made in this manner is another aspect of the invention. Such paper or cardboard exhibited increased strength and improved surface properties (making it a more valuable commodity) as shown in the examples below.

The invention extends to intimate particulate mixtures of starch and one or more additives as described above, which may be suspended or hydrated together for use in the process of the invention.

Starch/xanthan gum mixtures are shelf-stable and passable through the application equipment reliably, and SCMC solutions, alone or in conjunction with starch, are of particular value.

Example The Kinen Alliance will be explained in more detail with the following example.

Example 1 (a) 100 g of prior art wheat starch is dispersed in water ioooomj,
A slurry containing 1 (l) of starch solids was prepared at room temperature.

Brookfield 5C-4 Ada f1) with a moderate bob set to 20 revolutions per minute (rpm) and a thermostatic water circulator to increase the temperature from 20 degrees Celsius at a rate of 2 degrees per minute. The slough IJ-8 mJ was charged into a cylindrical container.

The dial was read continuously until the viscosity of the suspension rose rapidly and glued. The dial readings were plotted on graph paper. By extrapolation, the dulling temperature was determined to be 64 degrees Celsius.

Dendensula U-250, prepared as described above, has a molecular weight of about 100,000 and Cal. Degree of xymethyl substitution 0.
65 SCMC 1,25N (5% by weight of starch solids and total sous-7')/equivalent to 0.5 g of solution formulation)
was added. This mixture was mechanically stirred for 1 hour. Eight portions of this mixture were charged into a Brookfield 5C-4 cylinder and the procedure was repeated. The estimated gluing temperature was determined to be 60°C.

Further to the initial starch slurry of 250-, example (b),
It has the same molecular weight as SCMC used in , but the degree of substitution is 0.
8 SCMC1, 25 fl was added and the experiment was repeated. In this case, the estimated gluing temperature was determined to be 59°C.

Further, to the initial starch slurry of 2507ffj, example (
SCMC2,51 used in c) (10 starch solids
% by weight and corresponding to 1.0% of the general dispersion) were added.

The experiment was repeated and the gluing temperature was determined to be 58°C.

The experiment showed an unexpected decrease in the gluing temperature of starch suspensions as exemplified by a rapid increase in viscosity over a narrow temperature range. This is interpreted as a form of auxiliary dissolution effect, which is more evident when SCMC has a high degree of substitution and has a strong affinity for water release. Thus, when water and such SCMC enter starch particles during the early stages of particle breakage, the natural tendency of the SCMC molecules to unravel and swell leads to particle breakage at temperatures below those that would occur in the absence of SCMC. to assist.

Reducing the temperature, which allows the starch to glue and therefore form a more or less continuous film within the structure of the paper web, is of interest to paper makers as it is expected to reduce the thermal energy required to achieve gluing. Beneficial. Additionally, because gluing occurs early in the dry cefsilane phase of the papermaking process, there is more time for starch and cellulose fibers to interact beneficially.

Column 2 Ranks Hovla MacDougall Lt.
Commercially available starch particles IJ-250m, known as Ten5tar AB, manufactured by d. Processed. The amount of starch sedimentation was 2501nl for several days.
This was determined by noting the volume of clear liquid appearing at the top of the fluid when stored in a graduated glass cylinder.

The results were recorded and shown in Table 2 below.

Margin Table 2 below 38% Ten5tar Starch Slurry Rexa/Tangomuchi Volume of transparent liquid (Jnl) Based on total volume) 1 day 3 days 7 days 14 days 0.0 0 5 10 25
0.10 0 0 5 1
00.15 0 0 0
00.20 0 0 0
The procedure described in Of112 (a) was repeated using another non-dried commercial starch slurry. The starch slurry contains 18 grams of starch solids obtained by wet milling grains.
known as h. The results are shown in Table 3.

Margin Table 3: Volume of xanthan rubber transparent liquid: 000,
Note: The slurry used in the above experiment was treated with 0.2% dichlorophene to prevent microbial interference with the starch and polymer suspension.

The results of the above experiments show that xanthan gum added to commercial starch slurry prevents the settling of starch particles without the need for continuous shaking as in the prior art and therefore facilitates long-term storage. Show that it has a beneficial effect that provides a benefit.

Example 3 Blends of starch and oxymethyl cellulose and/or xanthan gum were prepared as shown in Table 4.

Table 4 A 100 0 0 0B 96
4 0 0C96040 D 99.6 0 0 0.4FJ95
．． 6 0 4 0.4F 95.6
4 0 0.4 250g of each blend with 75g of water
A 25 mm slurry was prepared and used for printing on handmade paper. The spray was such that in each case it provided 0.7 TrLl onto the dry paper. The above values are for a paper sheet with a nominal dry weight of 3.7 g and a dry starch or blend pick-up of 4.7 g.
Equal to 7chi.

The paper construction was bleached kraft with natural cation retention aids. After drying and calendering, the sheets were tested for burst strength with a Muen Lens Star. The average of the 10 tests was recorded and compared to an untreated paper made at the same time but sprayed with water over the starch slurry.

Table 5 Heading Kraft; Sea) 3.7g: Starch impregnation amount 4.7% No 14.2
0. OA 15.7
+10.5B 16
．． 5 +16.5C17,0+19
．． 7 0 17.0
+19.7E 17.2
+21.1F
17.5 +23.2 The experimental results shown in Table 5 show the beneficial effect of increasing the burst strength of paper by adding starch.

They further demonstrate additional benefits derived from the addition of polymers as described in the present invention to small proportions of starch.

The additional cost of making these additions is far outweighed by the commercial advantages to papermakers using the present invention.

Example 4 Foun an atomizer as described in the invention
A slurry prepared by diluting a commercially available starch slurry was distributed over the wire section of a drinier paper machine. The commercially available starch slurry had xanthan gum and SCMCtt introduced immediately after slurry production as a by-product of the process of extracting other components of the ground wheat. The proportions of materials used in this example were as follows: wheat starch solids 380 kg SCMC 18 parts xanthan gum 2 parts 9 parts water
A 600 kg paper machine produces 35 m/min at a speed of 400 m/min.
40 sheets of paper with a weight of fi/m2! It was set to produce 9. Commercially available cationic starch 1.5 was used in the paper machine composition.
% (dry) is combined.

The cationic starch acts in part as a way to provide the required burst strength and in part to aid in drainage as well as to assist in retaining the fibers on the wire section of the machine. Sura IJ- of the above composition has a per minute rate of 1.51 (
The flow was pumped into the meter at 0.57 kg starch solids per minute, representing 1.4 g of the dry weight of the paper. The slurry passes through a series diluter where it mixes with independently pumped water at υ51 per minute. The resulting diluted slurry of 1 min p6.51 was passed through an atomizer as described herein.

The atomizer is driven by an air motor set at 5000 revolutions per minute, producing droplets with an average diameter of 500 micrometers.

The slurry was applied to the paper over a period of 30 hours, and the sample
Samples were taken every hour. During this period, the addition of cationic starch to the composition was gradually reduced to zero, making the present invention a well-known and hitherto acceptable method of improving paper quality by adding starch-based products to paper machine compositions. compared with. The random results of this experiment are shown in Table 6.

Table 6 Selected waste + bleached waste 7): 50 g/m.

Starch moisture content 1.4% Cationic starch 1.5% Blank 2.80 0.0
56 0. OA 3.20 +
14 57 +1.8 cation dene f:yo,
Decrease to 8% B 3.41 +22 60
+6.7C3,36+20 62
+9.70 3.33 +19
59 +5.4 Decreased to cationic starch O E 3.46 +24 56
0.0* Parameter 1 Mullen rupture ratio” (
MBR) is defined as follows.

where MB = pressure in pounds per square inch to rupture a paper sample in the well-known Mie-Lench star used throughout the paper industry; GSM = weight of paper (,9); The burst ratio can be used to eliminate small changes in low weight that would otherwise affect the results of a destructive test.

The results show that the burst strength of papers already containing strength-enhancing additives was increased by the addition of starch.

Additionally, the Mullen burst strength ratio increased further as the previously used strength-enhancing additive was gradually reduced to zero. By the addition of DENSO/ which is modified as described in the present invention and applied in the form of droplets to the slip paper during production on the paper machine.
Better results may be produced than with another board starch previously deemed acceptable by those in the paper industry.

The results also show that the addition of starch, modified as described above and applied to the paper at an early stage of manufacture, increases the tensile strength of papers that have already had a tensile strength-enhancing additive, ie, cationic starch added.

Example j5 Addition of SCMC to paper during production using an atomizer A dispersion of SCMC was applied to paper using an atomizer and the flowmeter device described in Example 4. In this example, the modified starch slurry used in Example 4 was added with a molecular weight of approximately 100.0.
00 and carboxymethyl substitution degree 0.85. and solution 1
An aqueous solution of SCMC containing 20 g of dried SCMC per hour was used. Does the paper machine produce 40kl of dry paper per minute, as in fFIJ4? was set up to produce. S.C.
The flow rate of the MC solution was adjusted to 51 cm per minute (addition rate of 0.25% SCMC to the produced dry paper).

The results of this experiment are shown in Table 7.

Margin below
).

Table 7 Selected waste + bleaching craft: 5011/worn, SCMC
Impregnated amount 0.25%: Without starch 0.0 2.80 0.0 56
0.00.25 3.46 +23.6.

57 +1.8 The results shown in Table 7 indicate that SCMC with a relatively low molecular weight and high degree of carboxyl methyl substitution was applied to paper by the atomizer described in this specification at an early stage of production.
．． It shows the benefit of applying as little as 25 inches.

Various modifications and supplements can be made to the present invention.

For example, paper or paper? - by the incorporation of special atomizers into the machines used for the production of paper (as described above with respect to the spraying of SCMC liquids), and by the selective or alternative use of such atomizers with respect to other suspensions or solutions. The possibility of operating the machine is given.

For example, such an atomizer can be used with a sizing agent in the form of either a solution, emulsion or suspension. They can also be used with colorants in the form of either soluble dyes or insoluble pigment suspensions. They can also be used with oily substances, such as those applied for waterproofing or otherwise modifying paper. They can also be used with liquid forms of reactive resins that are added to the paper to increase wet strength or increase the resistance of the dry paper to water. In this aspect, the use of two or more atomizers placed above the wire section of the paper machine allows the application of some substances. The materials can provide further benefits by physically or chemically interacting with each other and with the paper to which they are applied.

By adjusting the position of the atomizer along the wire section of the paper machine, it is expected that the degree of penetration of the applied material will be controlled. For example, by applying a substance to a location of high moisture content in paper, such substance can penetrate into the body of the paper and therefore become an integral part of the paper. Conversely, application at points where the moisture has been reduced by drainage, suction or application of heat can retain the substance on the surface of the paper, and thus the substance becomes concentrated at or near the surface of the paper.

It is also anticipated that the atomizer can be used to apply the coating to the paper after the drying portion of the process is completed.

In this case, the atomizer forms part of a special machine used for applying pigments, resins, waxes, colorants or various solutions to the paper surface.

For SCMC solutions and dengue suspensions as described above, the benefits of droplet size separation from flow rate once incorporated into the machine are generally beneficial throughout the commercial papermaking process. Either the atomizers in question are associated with selective separate uses, or successive atomizers are provided at different points in the papermaking flow path, yet the required solution or suspension is ready for use when desired. It is expected that this will either be in permanent contact with the atomizer.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of an atomizer. 1... Inner cone, 2... Outer cone, 3... Bottom bearing, 4
... Central axis, 5 ... Center nozzle, 10 ... Teeth.

Claims (1)

[Claims] 1. A paper or cardboard manufacturing method applying a suspension or solution of a substance in a liquid, in which the substance in the liquid is continuously supplied to a rotary atomizer, and a spray is emitted from the rotary atomizer. A method consisting of causing the atomizer to fall onto the surface of paper or cardboard that moves relative to the atomizer. 2. Claim 1, wherein the rotary atomizer is a rotary atomizer substantially as described in British Patent No. 2,004,204B, British Patent No. 2,004,205B or British Patent No. 2,004,206B.
The method described in section. 3. Using a plurality of atomizers fed with the same or different substances in liquid, the atomizers receiving adjacent or overlapping longitudinal strips of substance from the atomizers, such that paper or cardboard moving through the machine 3. A method as claimed in claim 1 or 2, wherein the method is arranged across a paper or board making machine. 4. The atomizer is installed in a paper making machine using a plurality of atomizers fed with the same or different substances in a liquid, such that the paper or cardboard moving through the machine receives a continuous spray of substance from the atomizers. The method according to any one of claims 1 to 3, wherein the method is arranged vertically with a cardboard making machine. 5. The method according to any one of claims 1 to 4, wherein the liquid is water. 6. Any one of claims 1 to 5, wherein the atomizer is arranged with the bottom near the surface to which the liquid is applied.
The method described in section. 7. The method of claim 4, wherein the liquid is a viscous suspension or solution required to penetrate the paper and is applied early in the manufacturing process. 8. A method according to any one of claims 1 to 7, wherein the substance in the liquid is an aqueous starch suspension and is sprayed onto the paper web. 9. The method of claim 8, wherein the aqueous starch suspension contains a small amount of dissolved xanthan gum to stabilize the suspension. 10. The method according to claim 9, wherein the starch is in granular form. 11. Claims 8 and 9, wherein the aqueous starch suspension further comprises a small amount of sodium carboxymethylcellulose.
Or the method described in item 10. 12. Sizing agent, coloring material containing one or more substances,
8. A method according to any one of claims 1 to 7, comprising a reactive resin and a film-forming material. 13. In order to cause a surface effect on a substance in a liquid,
13. A method as claimed in any one of claims 1 to 12, in which the paper is sprayed after the drying part of the process. 14. The method of claim 13, wherein the substance is a wax, adhesive, pigment, dye or film-forming material. 15. The method according to claim 12 or 14, wherein the film-forming material is sodium carboxymethyl cellulose. 16. A papermaking additive consisting of an aqueous suspension of uncooked starch stabilized by a small amount of xanthan gum. 17. The papermaking additive according to claim 16, which is a non-dried starch slurry product of wet milled grains, to which xanthan gum is added. 18. The proportion of xanthan gum in the suspension water is 0.025.
18. A papermaking additive according to claim 16 or 17, wherein the amount is 1% by weight. 19. Claim 16, 17 or 18, wherein the suspension further comprises a small amount of sodium carboxymethylcellulose.
Paper-making additives as described in Section. 20. A method for producing a paper additive by adding a small amount of xanthan gum to a mixture of uncooked starch in water. 21. Paper production made by applying the papermaking additive according to any one of claims 16 to 19, or the papermaking additive produced by the method according to claim 20 using a rotary atomizer. Method.